Hydraulic fracturing can increase the rate of production of oil and gas from low-permeability reservoirs. Hydraulic fracturing increases the permeability of reservoir rocks by opening channels through which oil and gas can move. During a hydraulic fracturing procedure, a fluid is pumped through a wellbore under high pressure into a subterranean reservoir where it splits or fractures the reservoir rock. A proppant, like sand, is often added to the pumped fluid and is carried in suspension into the newly formed fractures. When pumping ceases, the fractures partially close on the proppant, leaving channels for oil and gas to flow to a recovery well.
High-pressure pumps are used to complete hydraulic fracturing procedures or “frac jobs.” These pumps have plungers that reciprocate within a pumping chamber to produce the extremely high pressures necessary break reservoir rocks underground. As the plungers reciprocate within the pumping chamber, the plungers cycle between high and low pressures and are subjected to high stress variations. The plungers also rub against sealing elements in the ends of the pumping chambers and, consequently, are worn and abraded by proppants and other materials carried in the pumped fluids.
Oilfield equipment manufacturers have made few provisions in their pumps for fixing pump plungers as they wear out. Typically, the plungers are located deep within a fluid end of a pump that is held together by a large number of heavy, threaded fasteners. To access the worn plungers, the fluid end and other pump components must often be disassembled. Although manufacturers provide strong and robust pumps, disassembly of pumps in the field is especially time-consuming and difficult to perform.